def test_eql_grav_jacobian():
"EQLGravity produces the right Jacobian matrix for single source"
model = PointGrid([-10, 10, -10, 10], 500, (2, 2))[0]
model.addprop('density', 1)
n = 1000
x, y, z = gridder.scatter([-10, 10, -10, 10], n, z=-100, seed=42)
data = sphere.gz(x, y, z, [model])
eql = EQLGravity(x, y, z, data, [model])
A = eql.jacobian(None)
assert A.shape == (n, 1)
assert_allclose(A[:, 0], data, rtol=0.01)
